On your first point, I don’t think it would be unusual for more people to turn to racism and simplistic, bone-headed views on immigration in the search for an explanation of why people are losing their jobs. Alternatively, these racist views could prevail whatever, but at a time of economic crisis it is more likely to change from something that people grumble about in the staff room to something that people go out and vote for.

As for Weimar, I don’t think that’s a useful comparison. Weimar had a long list of institutional and other problems, and the Nazis were not the only extremists gaining a lot of support.

And if their voters are already racist, then the scrutiny to which they will now be exposed won’t cost them any support. The Nazis were presumably heavily in the “spotlight” in the Weimar, and that didn’t seem to inspire the better angels of the electorate.